SUBDIAPHRAGMATIC VAGAL DEAFFERENTATION FAILS TO BLOCK FEEDING-SUPPRESSIVE EFFECTS OF LPS AND IL-1-BETA IN RATS

To evaluate the role of subdiaphragmatic vagal afferent fibers in medi ating the inhibition of food intake produced by peripheral administrat ion of bacterial lipopolysaccharide (LPS) and the proinflammatory cyto kine interleukin-1 beta (IL-1 beta), we assessed the ability of 100 mu g/kg ip LPS and 2 mu g/kg ip human recombinant IL-1 beta to suppress solid food intake during the first 3 and 6 h of the dark cycle in rats with selective vagal rootlet deafferentation (SDA, n = 15) and in sha m surgical control rats (Con, n = 17). SDA was produced by a combinati on of dorsal subdiaphragmatic truncal vagotomy and left vagal afferent rootlet transection as the left vagus enters the caudal brain stem. B oth LPS and IL-1 beta significantly suppressed food intake at 3 and 6 h in both Con and SDA rats, and SDA failed to attenuate the LPS-and IL -1 beta-induced reductions in food consumption relative to the suppres sion seen in controls. Peripheral administration of the gut-brain pept ide cholecystokinin (CCK) suppressed 30-min 12.5% liquid glucose consu mption in control, but not in SDA rats, consistent with previous demon strations of the role of subdiaphragmatic vagal afferents in the media tion of CCK satiety. These data demonstrate that subdiaphragmatic vaga l afferents are not necessary for the feeding-suppressive actions of p eripherally administered LPS and IL-1 beta and suggest that peripheral LPS and IL-1 beta may inhibit food intake via humoral and/or splanchn ic visceral afferent pathways.